<!DOCTYPE html>
<html>

<head>
  <meta charset="UTF-8">
  <title>JsStore Webpack Example</title>
  <script>
    if (!Array.prototype.findIndex) {
      Object.defineProperty(Array.prototype, 'findIndex', {
        value: function (predicate) {
          // 1. Let O be ? ToObject(this value).
          if (this == null) {
            throw new TypeError('"this" is null or not defined');
          }

          var o = Object(this);

          // 2. Let len be ? ToLength(? Get(O, "length")).
          var len = o.length >>> 0;

          // 3. If IsCallable(predicate) is false, throw a TypeError exception.
          if (typeof predicate !== 'function') {
            throw new TypeError('predicate must be a function');
          }

          // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
          var thisArg = arguments[1];

          // 5. Let k be 0.
          var k = 0;

          // 6. Repeat, while k < len
          while (k < len) {
            // a. Let Pk be ! ToString(k).
            // b. Let kValue be ? Get(O, Pk).
            // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
            // d. If testResult is true, return k.
            var kValue = o[k];
            if (predicate.call(thisArg, kValue, k, o)) {
              return k;
            }
            // e. Increase k by 1.
            k++;
          }

          // 7. Return -1.
          return -1;
        },
        configurable: true,
        writable: true
      });
    }
  </script>
</head>

<body>
  <div id="app">

  </div>

</body>

</html>